1. Field of the Invention
The invention relates to a glass or glass-ceramic pane reflecting infrared radiation as well as a method for the production thereof. In particular, the invention relates to a front pane for an oven or a fireplace, as well as a fireproof glazing.
2. Description of Related Art
Panes reflecting infrared radiation, in particular, baking-oven panes or fireplace viewing panes are known. Usually these involve a substrate glass made of glass or glass ceramics, which is provided with a coating that has a lower transmission in the infrared region than in the region of visible light. Thus, the user can look inside the oven or the fireplace, whereby, for example, infrared radiation arising in the oven due to a fire is only partially emitted into the environment.
Based on the structure reflecting infrared radiation, therefore, not only is the heating of articles in the vicinity of the oven reduced, but also a warming of the pane and the environment of the pane to temperatures that could lead to combustion upon contact can be avoided.
Conventional coatings for glass-ceramic panes are constructed, for example, of tin-doped indium oxide. Further, aluminum-doped tin-oxide layers as well as fluorine-doped tin-oxide layers are known. A higher reflectance can be achieved with such coatings for wavelengths even starting from approximately 2000 nanometers (nm).
However, it has been shown to be a disadvantage of known coatings reflecting infrared radiation, that with a high heat load, particularly at temperatures over 450 degrees Celsius (°C.), the layers lose their reflecting effect in the infrared region, in part permanently.
Thus, only long-term temperature loads of 500° C. at most can be attained. These types of glass-ceramic panes are thus not optimally suitable as panes for fireproof applications.
In addition, temperatures of approximately 900° C. are reached in the ceramicizing process in the production of glass ceramics from green glass. After heating to this temperature, conventional layers reflecting infrared radiation largely lose their effect.
It is a more complex process to introduce a layer reflecting infrared radiation after the ceramicizing process; in particular, glass panes that are shaped, especially bent in the course of the ceramicizing process, and thus are brought to the desired final shape can be provided with a uniform coating only in a very complex procedure.